Chemistry Reference
In-Depth Information
SCHEME 4.13.
Hydrolysis of less reactive
N
-sulfonatooxyacetanilides.
appear to generate
(Scheme 4.13). The pH-dependent decomposition is
only observed at pH 1-8 in cases in which
k
o
is smaller than about 10
4
s
1
at 80
C
or about 10
7
s
1
at 20
C.
18,94
Hydrolysis kinetics of the pivalic acid esters
58e
and
58f
(Scheme 4.14) at 40
C were
61a-d
6.0.
95
Reaction
products are summarized in Scheme 4.14. Products and product ratios derived from
the
meta
-bromo ester
s
þ
with a
r
þ
of
pH independent at pH 1-7 and
k
obs
correlated with
and
with the Bamberger rearrangement of
N
-(3-bromophenyl)hydroxylamine, with the
exception of the rearrangement products.
95
The rearrangement products
61b
were consistent with those previously attributed to
58e
62
appear to
be derived from intramolecular aminolysis of
63
since
63a
, generated
in situ
was
shown to undergo the indicated reactions.
95
Decomposition of
generated only 4-nitroaniline (70%) and 4,4
0
-dinitroazox-
ybenzene (10%) (Scheme 4.14). These products could have been derived from a
triplet nitrene or a triplet nitrenium ion.
95
Homolysis to generate radical intermedi-
ates was ruled out because of the nearly quantitative yield of pivalic acid. The
pivaloxy radical would have undergone decarboxylation to generate CO
2
and the
61d
